Originally Posted by A_Lee

Unfortunately the dayrooms are way over-budget for the OP's specified maximum 1500 THB even for the minimum time-block of 4 hours. And if 8 hours or more the amount they charge gets to be silly. If you want a room for that long, it makes no sense to not get a room outside the airport, unless entering Thailand is a hassle or problem for you. For 4 hours, I suppose it's debatable as to whether one is better off with a dayroom or going outside. I'd probably opt for the dayroom myself being you'll lose considerable time going in and out of immigration and in a taxi to/from the hotel.